The prescribing information for Propecia (finasteride 1 mg) describes three double-blind, randomized, placebo-controlled studies of 12-month duration. Their two primary endpoints were hair count and patient self-assessment. A 2023 network meta-analysis that counted trials reporting changes after 24 weeks concluded that finasteride in men was not statistically different from placebo. This guide sets out what each source measured.
What the label's 12-month studies measured
In the label's account, the two secondary endpoints were investigator assessment and ratings of photographs. The label says hair counts were assessed by photographic enlargements of a representative area of active hair loss. All men, whether treated with finasteride or placebo, were instructed to use a specified, medicated, tar-based shampoo.
| Measure at 12 months | What the label says |
|---|---|
| Hair count | A 107-hair difference from placebo |
| Further hair loss (any decrease in hair count from baseline) | 58% of men in the placebo group, compared with 14% of men treated with Propecia |
| Investigators rating increased hair growth | 65% of men treated with Propecia, compared with 37% in the placebo group |
| Independent panel's photograph ratings, increase | 48% of men treated with Propecia, compared with 7% of men treated with placebo |
For patient self-assessment, the label says overall improvement compared with placebo was seen as early as 3 months (p<0.05), with improvement maintained over 5 years.
What the label reports at 5 years
The label states that hair count was maintained above baseline throughout the 5 years of the studies. Because the decline in the placebo group was more rapid, the difference between groups kept increasing, resulting in a 277-hair difference. At 5 years, 100% of men in the placebo group demonstrated hair loss, compared with 35% of men treated with Propecia.
In the 5-year photographic assessment, 48% of men treated with Propecia demonstrated an increase in hair growth, 42% were rated as having no change and 10% were rated as having lost hair when compared to baseline. For men treated with placebo, the figures were 6%, 19% and 75%.
What published trials and reviews added
A 1998 report from the Finasteride Male Pattern Hair Loss Study Group described two 1-year trials in which 1553 men (18 to 41 years of age) received oral finasteride 1 mg/d or placebo, and 1215 men continued in blinded extension studies for a second year. Hair count was measured in a 1-inch diameter circular area (5.1 cm2) of balding vertex scalp (baseline = 876 hairs), with 107 and 138 hairs versus placebo at 1 and 2 years, respectively (P < .001).
A 1999 frontal scalp study reported a significant increase in frontal hair count (P < .001) and significant improvements in patient, investigator, and global photographic assessments. A 2002 five-year report concluded that long-term treatment with finasteride 1 mg/day was well tolerated, led to durable improvements in scalp hair growth, and slowed further progression of hair loss. A 2015 meta-analysis of 34 finasteride trials found that none had adequate safety reporting, 19 were partially adequate, 12 were inadequate, and 3 reported no adverse events.
A 2012 photographic assessment paper reported statistically significant (P ≤ .05) hair growth versus placebo at 24 months in all scalp regions. Its authors note that the studies enrolled men with vertex pattern hair loss, so the findings may not be extrapolated to men with predominantly anterior/mid scalp, frontal, or temporal hair loss.
A 2017 meta-analysis reported that all treatments, including 1 mg finasteride in men, were superior to placebo (P < .00001) in its 5 meta-analyses. A 2025 network meta-analysis concluded that, among FDA-approved treatments, finasteride 1 mg/day was the most effective oral option.
One 2023 network meta-analysis found no difference from placebo
A systematic review and Bayesian network meta-analysis in Frontiers in Medicine concluded that finasteride in men was not statistically different from placebo. It included only randomized, placebo-controlled trials with at least 20 patients that reported changes in terminal hair density after 24 weeks. The abstract text cited here does not state the finasteride dose or the trials pooled.
The label studies ran 12 months, while this review's inclusion rule refers to 24 weeks. Those are different time frames, so the two results do not describe the same follow-up point.
The abstract also carries a conflict of interest statement. It says Arbor Life Labs owns ALRV5XR, a product tested in the analysis, and that one of the authors was employed by that company. The statement does not say whether this tie affected the analysis.
What this does not tell you
Trial results describe groups of men, not any one man. Hair counts came from defined areas of scalp, not the whole scalp. The 12-month and 5-year label figures, the 24-month paper and the 24-week review are separate measurements, so their numbers should not be combined. The 2015 meta-analysis above concluded that published reports of clinical trials provide insufficient information to establish the safety profile for finasteride in the treatment of androgenetic alopecia. A licensed provider decides whether finasteride suits a particular man.